Yarn feed means for knitting machines



Jan. 31, 1967 P. H. EBERLE 3,301,015

YARN FEED MEANS FOR KNITTING MACHINES Filed Sept. 10, 1964 FlE- 1 I NVENTOR,

"Pw/ H [bar/e ATTORNEY.

United States Patent Ofifice This invention relates to circular knitting machines and more particularly to means for controlling the feeding of stretch type yarns to the fabric forming means of such machines.

In circular knitting machines yarn feeding means is provided which is operated by pattern means to introduce the yarns to the needles to be formed into tubular fabric thereby and to remove the yarns from knitting position according to a desired pattern. The machines are also provided with yarn severing and holding means which includes suction means for engaging and holding the severed ends of both ingoing and outgoing yarns and mechanically operated clamping means for holding the ends of the inactive yarn when the suction means is de-energized. The clamping means is normally in active position to hold the ends of the inactive yarns and the clamp is raised to inactive position to release the yarns when a yarn is moved to knitting position and when a yarn is removed from knitting position. Simultaneously with the movement of the clamp to release the yarns, the suction means is energized to again engage and hold the ends of all of the inactive yarns until the ingoing yarn is taken by the needles of the machine and knitted into the fabric. Also the suction means engages and holds the end of an outgoing yarn after it is severed until the clamp is returned to active yarn holding position. While this type of holding means provides a positive control for nylon yarns and other similar yarns employed in the knitting process which have little if any elasticity or stretchability, the use of stretch type yarns such as raw polyurethene yarn and the like, which have a high degree of elasticity, causes difficulty in that such yarn tends to contract to its normal condition when removed from knitting position and severed with the result that the end thereof is withdrawn from the suction tube and control by the suction tube is lost when the yarn is again to be returned to knitting position.

It is therefore an object of the invention to provide means in a circular knitting machine for overcoming the above noted and other difiiculties heretofore encountered in the feeding of synthetic type stretch yarns to the fabricating means of the machine.

Another object of the invention is the provision of means in a circular knitting machine for feeding stretch type yarns to the fabricating means of the machine which means acts to overfeed an excess length of the yarn between the yarn supply and feed finger for the yarn after it is removed from knitting position.

A further object of the invention is the provision of means in a circular knitting machine for feeding yarn to the fabricating means of the machine which means includes a free running roller over which the yarn passes from the yarn supply to the feed finger means for the yarn, the roller being rotated by the feeding movement of the yarn and acting to feed a surplus length of the yarn between the supply and feeding means when the yarn is removed from feeding position. The machine i also provided with means for severing the yarn and means for removing the excess length of yarn between the roller and feeding means when the yarn is removed from feeding position and severed.

With these and other objects in view which will become Patented Jan. 31, 1967 apparent from the following detailed description of the illustrative embodiment of the invention shown in the accompanying drawings, the invention resides in the novel features of construction and cooperation of parts as hereinafter more particularly pointed out in the claims.

In the drawings:

FIG. 1 is an elevational view of a portion of a circular knitting machine having yarn feeding means according to the invention applied thereto, the parts being shown in their positions immediately following severance of a yarn removed from knitting position;

FIG. 2 is a view of the mechanism of FIG. 1 showing overfeeding of the yarn prior to its severance; and

FIG. 3 is a view on an enlarged scale taken in the direction of the arrow 3 of FIG. 1.

Referring to FIG. 1 there is shown a portion of a circular knitting machine including needles It), a dial mechanism 11 having usual dial bits or transfer elements (not shown), and feed fingers 12 which are moved between lowered positions to feed their yarn 13 to the needles to be knit into fabrics such as ladies hosiery and raised inactive positions. Conventionally the yarns 13 are of nylon or the like and are fed from supply cones or bobbins 15 which are supported on a bobbin stand or bracket 16 secured in fixed position on the framework of the machine. The yarns normally pass through tensioning means 18 carried on a bracket 20 secured to a post 21 carried in the bobbin stand, from the tension means to guide eyelets one of which is shown at 22, and from the latter to the feed fingers 12.

The machine is also provided with yarn severing and holding means indicated at 25 which is generally of the type shown in US. Patent 3,097,512, issued July 16, 1963 and which includes a toothed annulus 26 mounted on the dial mechanism for rotation with the dial bits, a cutter member 27 which is mounted in fixed position on an upper dial cap member 30 of the dial mechanism for engagement with the teeth of the annulus 26. Also included in the mechanism 25 is a suction tube 31 which is connected to an air source adapted to cause air to flow into the open 'end of the tube to hold the ends of yarns extending from the inactive yarn fingers 12, and a restraining member or clamp 32 for the yarns between the yarn fingers and suction tube in the manner set forth in said Patent No. 3,097,5 12.

When the yarn is to be removed from knitting position, the suction tube 31 is energized to hold the previously inactivated yarn ends and the clamp 32 is raised to inactive position to release the latter yarns. The yarn finger 12 is then raised to inactive position and the yarn therefrom is carried into engagement with a tooth of the annulus 26 and the annulus then carries the yarn beneath the clamp 32 and suction tube 31 and to the cutter member 27 for severance adjacent the last needle to knit the yarn and the end of the severed yarn is then withdrawn into the suction tube. When the newly inactivated yarn is replaced by another yarn the end of the latter yarn is held by the suc tion tube while the clamp is in inactive position until this yarn is taken by the first needle to knit it. The newly inserted yarn is then carried by the annulus to the cutter member for severance and the waste end of yarn is withdrawn through the suction tube. After the inactivated yarn and/ or newly inserted yarn are severed the clamp is returned to clamping engagement with the ends of the inactive yarns and the suction tube is again de-energized until another yarn change is made.

Where the fabric i to be knit of uncovered natural rubber yarn or a synthetic stretch type yarn such as raw or uncovered polyurethene yarn, generically termed spandex yarn and sold by E. I. du Pont under the trademark Lycra, to provide compressive force to the fabric, this yarn is commonly fed to the needles 10 with as little tension as possible. However, both rubber and raw polyurethene yarns tend to adhere to even the most highly polished surfaces with the result that the various guide members employed in the feeding path of the yarn from the supply cone to the needles causes some stretch in the yarn. Consequently when this yarn is removed from knitting position and severed it tends to contract to its normal length with the result that the end is withdrawn from the suction tube 31 when the tube is de-energized and control of the yarn by the tube is lost when the yarn is again to be returned to knitting position.

In order to overcome this condition according to the instant invention, a stretch yarn indicated at 35 is fed from a supply cone 36 carried on the bracket 16 over a roller 37 and thence through one of guide eyelets 22 t the finger 12 for the yarn. The roller 37 is mounted for free rotation on a stud 40 carried on a hanger member 41 secured to the bracket 20. The yarn 35 is guided along its path from the cone 36 over the roller 37 and thence to the eyelet 22 by a guide member 42 secured in fixed position on the hanger member 41 by the stud 46 (FIGS. 1 and 3).

During feeding of the yarn 35 to the needles 10 to be formed thereby into fabric the yarn rotates roller 37 with a surface speed which is substantially the same as the linear feeding speed of the yarn to the needles. The momentum of the roller 37 which is developed by the feeding of the yarn not only acts to provide sufiicient pull on the yarn to overcome slight tension variations in the yarn at the cone 36 to thereby maintain a substantially constant tension in the yarn as it is taken by the needles, but this momentum also causes the roller to overfeed a surplus length of yarn between the roller and feed finger 12 as indicated at 45 in FIG. 2, when the yarn requirement is discontinued as the feed finger 12 is raised to inactive position. As a tooth of annulus 25 carries the yarn beneath the suction tube 31 and the yarn is cut by cutter member 27 this surplus length supplies more than sufiicient yarn to enable the yarn to contract as the tension thereon is released the excess yarn then being drawn into the tube 31. Hence notwithstanding the contraction of the yarn the suction tube will maintain its temporary control thereon. The clamp is then operated to clamp the elastic yarn as well as the other inactivated yarns, and the suction tube is de-energized until another yarn change is to be made.

As previously explained, the yarns with which the present mechanism is used are of a character to tend to adhere even to a highly polished metal surface such as that of the roller 37. Nevertheless if the roller is of excessive weight or is mounted on bearings having excessive friction the adherence to or frictional contact of the yarn with the roller may be insufficient to overcome the inertia of the roller when the yarn is fed. At the same time the roller must be of a mass and have a sufiiciently good bearing that its continued rotation, to draw the surplus of yarn when the yarn feeding stops, is insured. It has been found that the above requirements are met by the use of an aluminum roller having for example an outer diameter of five-eighths inch and a length of five-eighths inch, the roller mounting providing a limited relatively friction free bearing surface. It will be appreciated that the invention is not limited to a roller of the specific dimensions and material described above as other sizes and diameters of rollers may be used which will start rotation upon the feeding of the yarn and overrun when feeding stops.

Of course the improvements specifically shown and described by which the above results are obtained may be changed and modified in different ways without departing from the invention herein disclosed and hereinafter claimed.

What is claimed is:

1. In a circular knitting machine having a circle of needles, yarn feeding means movable from inactive position to active position to feed yarn to said needles to be formed into knitted fabric, a supply cone for the yarn, a rotatable roller positioned between said cone and said feeding means and driven by said yarn during its movement from said cone to said feeding means when said feeding means is in active position, said roller acting to feed a surplus length of yarn between said roller and said feeding means when said feeding means is moved to inactive position, means for severing said yarn between said feeding means and said needles when said feeding means is moved to inactive position, and means interposed between said severing means and said feeding means for taking up an excess of said surplus length of yarn between said roller and said feeding means follow ing severance of said yarn by said severing means.

2. In a circular knitting machine having a circle of needles, yarn feeding means movable from inactive posi tion to active position to feed yarn to said needles to be formed into knitted fabric, a supply cone for the yarn, means interposed between said cone and said feeding vmeans for maintaining substantially uniform withdrawal of said yarn from said cone as said yarn is fed to said needles by said feeding means, said interposed means being driven by said yarn and acting to feed a surplus length of yarn between said withdrawing means and said feeding means when said feeding means is moved to inactive position, means for severing said yarn between said feeding means and said needles when said feeding means is moved to inactive position, and means inter posed between said severing means and said feeding means for removing the excess of said surplus length of yarn between said withdrawing means and said feeding means following severance of said yarn by said severing means.

3. In a machine according to claim 2 in which said withdrawing means compromises a roller and there is guide means associated with said roller for maintaining said yarn in engagement with said roller. v

4. In a circular knitting machine having a circle of needles, yarn feeding means movable from inactive posi-' tion to active position to feed yarn to said needles to be formed into knitted fabric, a supply cone for said yarn, means for severing said yarn between said feeding means and said needles when said feeding means is moved to inactive position, and means between said severing means and said feeding means for engaging and holding the severed end of said yarn when said feeding means is again moved to active position, in combination with freely rotatable roller over which said yarn passes in its path from said supply cone to said feeding means, said roller being driven by said yarn when said feeding means is in active position to feed said yarn to said needles, said roller acting through its own momentum to feed a surplus length of said yarn between said roller and said feeding means when said feeding means is moved to inactive position, and said engaging and holding means acting to remove an excess of said surplus length of yarn following severance of said yarn by said severing means.

References Cited by the Examiner UNITED STATES PATENTS 2,532,467 12/1950 St. Pierre 66146 X 2,972,245 2/1961 York et al 66146 3,097,513 6/1963 Pike et a1. 66-l40 X FOREIGN PATENTS 955,038 4/1964 Great Britain.

MERVIN STEIN, Primary Examiner.

W. C. REYNOLDS, Examiner. 

2. IN A CIRCULAR KNITTING MACHINE HAVING A CIRCLE OF NEEDLES, A YARN FEEDING MEANS MOVABLE FROM INACTIVE POSITION TO ACTIVE POSITION TO FEED YARN TO SAID NEEDLES TO BE FORMED INTO KNITTED FABRIC, A SUPPLY CONE FOR THE YARN, MEANS INTERPOSED BETWEEN SAID CONE AND SAID FEEDING MEANS FOR MAINTAINING SUBSTANTIALLY UNIFORM WITHDRAWAL OF SAID YARN FROM SAID CONE AS SAID YARN IS FED TO SAID NEEDLES BY SAID FEEDING MEANS, SAID INTERPOSED MEANS BEING DRIVEN BY SAID YARN AND ACTING TO FEED A SURPLUS LENGTH OF YARN BETWEEN SAID WITHDRAWING MEANS AND SAID FEEDING MEANS WHEN SAID FEEDING MEANS IS MOVED TO INACTIVE POSITION, MEANS FOR SEVERING SAID YARN BETWEEN SAID FEEDING MEANS AND SAID NEEDLES WHEN SAID FEEDING MEANS IS MOVED TO INACTIVE POSITION, AND MEANS INTERPOSED BETWEEN SAID SEVERING MEANS AND SAID FEEDING MEANS FOR REMOVING THE EXCESS OF SAID SURPLUS LENGTH OF YARN BETWEEN SAID WITHDRAWING MEANS AND SAID FEEDING MEANS FOLLOWING SEVERANCE OF SAID YARN BY SAID SEVERING MEANS. 